MIG WELDER 131MIG WELDER 131MIG WELDER 131MIG WELDER 131MIG WELDER 131

ASSEMBLY AND OPERATING INSTRUCTIONS

3491 Mission Oaks Blvd., Camarillo, CA 93011Visit our Web site at http://www.harborfreight.com

Copyright © 2003 by Harbor Freight Tools®. All rights reserved. No portion ofthis manual or any artwork contained herein may be reproduced in any shapeor form without the express written consent of Harbor Freight Tools.

For technical questions and replacement parts, please call 1-800-444-3353

06098

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(Peak)

12/03

Specifications

ITEM DESCRIPTION

Welding Current 25 ~ 85 amps

Duty Cycle20% at 75 amps; 45% at 50 amps; 90% at 35 amps;100% at 25 amps

Power Consumption 120 VAC, 21 amps at 60 Hz

Open Circuit Voltage 19 to 30 volts

Heat Control 25 ~ 85 amps, variable

Ground Cable 6 feet, 4 AWG, single instulation, grounding clamp.

Torch Power Cable 6 feet, 8 AWG, single insulation

Power Cord 6 feet, 3-core, 14 AWG, UL® Listed; 3-prong plug

Thermal OverloadProtection with Light

Automatic shutdown and restart after cool down

Wire Size0.023 to 0.035 inch steel and stainless steel0.030 to 0.035 inch aluminum; 0.030 flux core

Welding Material Size 22 gauge to 5/32"

Wire Spool Size 4 inch spool diameter

Weight 55.1 lbs.

Accessories

1 - Hand held shaded face shield1 - Brush Hammer1 - Wheel Kit1 - 2 lb. spool of flux wire

Save This Manual

You will need the manual for the safety warnings and precautions, assembly instructions,operating and maintenance procedures, parts list and diagram. Keep your invoice with thismanual. Write the invoice number on the inside of the front cover. Keep the manual andinvoice in a safe and dry place for future reference.

Safety Warnings and Precautions

WARNING: When using tool, basic safety precautions should always be followed toreduce the risk of personal injury and damage to equipment.

Read all instructions before using this tool!

1. Keep work area clean. Cluttered areas invite injuries.

2. Observe work area conditions. Do not use machines or power tools in damp or wetlocations. Don’t expose to rain. Keep work area well lighted. Do not use electricallypowered tools in the presence of flammable gases or liquids.

3. Keep children away. Children must never be allowed in the work area. Do not let themhandle machines, tools, or extension cords.

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4. Store idle equipment. When not in use, tools must be stored in a dry location to inhibitrust. Always lock up tools and keep out of reach of children.

5. Do not force tool. It will do the job better and more safely at the rate for which it wasintended. Do not use inappropriate attachments in an attempt to exceed the tool capacity.

6. Use the right tool for the job. Do not attempt to force a small tool or attachment to dothe work of a larger industrial tool. There are certain applications for which this tool wasdesigned. Do not modify this tool and do not use this tool for a purpose for which it wasnot intended.

7. Dress properly. Do not wear loose clothing or jewelry as they can be caught in movingparts. Protective, electrically non-conductive clothes and non-skid footwear arerecommended when working. Wear restrictive hair covering to contain long hair.

8. Use eye and ear protection. Always wear ANSI approved, arc shaded, impact safetyfull face shield when arc welding. Wear an ANSI approved dust mask or respirator whenworking around metal, chemical dusts, fumes and mists.

9. Do not overreach. Keep proper footing and balance at all times. Do not reach over oracross running machines.

10. Maintain tools with care. Keep tools sharp and clean for better and safer performance.Follow instructions for lubricating and changing accessories. Inspect tool cordsperiodically and, if damaged, have them repaired by an authorized technician. Thehandles must be kept clean, dry, and free from oil and grease at all times.

11. Disconnect power. Unplug tool when not in use.

12. Remove adjusting keys and wrenches. Check that keys and adjusting wrenches areremoved from the tool or machine work surface before plugging it in.

13. Avoid unintentional starting. Be sure the switch is in the Off position when not in useand before plugging in. Do not carry any tool with your finger on the trigger, whether it isplugged in or not.

14. Stay alert. Watch what you are doing, use common sense. Do not operate any tool whenyou are tired.

15. Check for damaged parts. Before using any tool, any part that appears damaged shouldbe carefully checked to determine that it will operate properly and perform its intendedfunction. Check for alignment and binding of moving parts; any broken parts or mountingfixtures; and any other condition that may affect proper operation. Any part that is damagedshould be properly repaired or replaced by a qualified technician. Do not use the tool ifany switch does not turn On and Off properly.

16. Guard against electric shock. Prevent body contact with grounded surfaces such aspipes, radiators, ranges, and refrigerator enclosures.

17. Replacement parts and accessories. When servicing, use only identical replacementparts. Use of any other parts will void the warranty. Only use accessories intended foruse with this tool. Approved accessories are available from Harbor Freight Tools.

18. Do not operate tool if under the influence of alcohol or drugs. Read warning labelson prescriptions to determine if your judgment or reflexes are impaired while taking drugs.

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If there is any doubt, do not operate the tool.

19. Maintenance. For your safety, service and maintenance should be performed regularlyby a qualified technician.

20. Use proper size and type extension cord. If an extension cord is required, it must be ofthe proper size and type to supply the correct current to the tool without heating up.Otherwise, the extension cord could melt and catch fire, or cause electrical damage tothe tool. This tool requires use of an 120 VAC extension cord of 20 amps minimumcapability (up to 30 feet), with wire size rated at 10 AWG. Longer extension cords requirelarger size wire. If you are using the tool outdoors, use an extension cord rated for outdooruse (signified by “WA” on the jacket).

21. Pacemaker safety warning. People with pacemakers should consult with theirphysician(s) before using this product; operation of equipment in close proximity to aheart pacemaker could cause interference or failure of the pacemaker.

Note: Performance of this tool may vary depending on variations in local line voltage. Exten-sion cord usage may also affect tool performance.

Warning: The warnings, cautions, and instructions discussed in this instruction manualcannot cover all possible conditions and situations that may occur. It must be under-stood by the operator that common sense and caution are factors which cannot bebuilt into this product, but must be supplied by the operator.

Arc Welding Safety Warnings and Precautions

Warning: This product, when used for welding and similar applications, produces chemi-cals known to the State of California to cause cancer and birth defects (or other repro-ductive harm). California Health & Safety Code 25249.5, et seq.

1. Avoid electrical shock. Do not permit electrically live parts, cables, or electrodes tocontact skin, clothing, or gloves. Protective clothing should be free of holes, dry, andANSI approved.

This unit draws enough current to cause serious injury or death. Before turning the welderon, check the electrode holder to be sure that there are no protruding screw heads, andthat all insulation is secure. Do not weld unless you are insulated from ground and thework piece.

2. Avoid breathing fumes or gases. They can cause serious health problems. Use anactive ventilation system directly above the welding area. Keep your head out of thefumes.

3. Avoid eye and body damage. Arc rays and infrared radiation can injure eyes and burnskin. Wear ANSI approved eye and body protection. Do not allow viewing by visitorswithout proper eye and body protection. Use a Face Shield with arc shaded filter plate.

4. Know proper arc welding practices. Read and understand this instruction manual, aswell as your employer’s safety practices for arc welding.

5. Connect only to a code approved power source. Connect only to a grounding powersource conforming to the National Electrical Code and Local Codes.

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6. Avoid fire and explosion. Remove flammable and explosive material from at least 35feet from the welding arc to prevent welding sparks or molten metal from starting a fire.Keep a type ABC fire extinguisher within easy reach. Thoroughly clean the object beingwelded of any paint, grease, or other foreign material.

7. Avoid being burned. Always wear ANSI approved welding gear: leather gloves, leatherapron, and shoes.

8. Wear proper clothing when welding. Use flameproof, welding type gloves. Wear cufflesspants and pocketless shirt. Both must be free of oil and grease. Wear high-topped, safetyto shoes with rubber soles.

Unpacking

When unpacking, check to make sure the following parts are included.

Welding Torch (15)

Brush Hammer

Ground Cable with Clamp

Handheld ShadedFace Shield

Line Cord (13)

If any parts are missing or broken, please call Harbor Freight Tools at the number on the coverof this manual as soon as possible.

REV 05/04

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Assembly

MIG Welder Unit

1. Insert the Handle (4) into the Handle Sockets (3) and mount the Handle Sockets to theSide Panel B (1) top using supplied hardware.

2. Lift Side Panel B (1) all the way to expose the wire spool and Wire Feed Mechanism(10).

3. Remove the Nut from the Wire Spool Axle (9). Place the Wire Spool over the Axle withthe wire exiting the spool over the top. Refer to photos above. Replace the Spool AxleNut.

4. Open the Wire Feed Mechanism (10) as shown in the photo (top-right).

5. Feed and guide the spool wire into the Wire Feed Mechanism, past the feed wheels(C), and into the Welding Torch / Cable (15).

It will help if the Welding Torch / Cable (15) is straightened out as much as possible.Push in until the wire comes out the Welding Torch head. If it cannot be fed manuallyall the way out, it can be fed automatically when the welding unit is powered up.

6. Close the Feed Mechanism (10) over the wire, and adjust the feed tension (D) ifnecessary.

7. Check that +/– cables to connection Knobs (29) are correct. See photo (top-left).

When using non-flux wire and protective gas, connect wire cables as shown in photo.For 0.9 flux cored wire, no gas is required. Reverse cable connections.

8. Close the Side Panel B (1).

Wire Feed Mechanism (10)Wire SpoolWire Spool Axle (9)

Side Panel B (1)

(C)

(D)

(29)–

+

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Handheld Shaded Face Shield

Assemble the Handheld Shaded Face Shield as illustrated in its Assembly Drawing at theend of this manual.

Operation

Controls and Indicators

Welding

Caution: Before arc welding, read and understand all safety precautions and warningslisted on pages 2 through 5.

1. If using non-flux core wire, connect and secure the Argon / CO2 gas hose to the rear ofthe MIG Welder. (If using flux core wire, protective gas is not required.)

2. Attach the Ground Cable with Clamp (14) as close as possibleto the metal object to be welded, or to the metal work benchwhere the object is mounted and electrically connected.

3. Set the desired welding current (30~120 amps) for the type ofmetal being welded using the Min/Max Switch and 1/2 PowerLevel Switch.

Refer to the power setting table on the next page. Thinner metals use lower current.Heavier metals use higher current.

4. Verify that the On/Off Switch is in the OFF position, then plug the MIG Welder LineCord into a dedicated, 120 VAC, 20 amp line with delayed action type circuit breakeror fuses. If an extension cord is used, it must have the following wire size: up to 30 feet,use 10 AWG size wire; 30 to 50 feet, 8 AWG wire; Over 50 feet, 6 AWG wire.

On / Off Switch

Min / Max Switch

1 / 2 Power Level Switch

Overload-shutdownIndicator Lamp

Wire Feed Speed Control

Line Cord

Ground Cable with Clamp (14) Welding Torch Cable (15)

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Rated DC Output Set Power Switches Amps Duty Cycle Volts

Maximum OCV 28V

Min. -- 1 25 100% 15.2

Min. -- 2 35 90% 15.7

Max. -- 1 50 45% 16.5

Max. -- 2 75 20% 17.7

5. While holding the Welding Torch handle, with the electrode wire clearly out of the wayof any grounded objects, turn the On/Off Switch to the ON position.

6. Momentarily press the Welding Torch trigger switch to test the wire feed speed.

Adjust the speed by turning the Wire Feed Speed Control knob.

7. Orient yourself on the area to be welded, then hold the Arc Shaded Face Shield overyour eyes.

Warning: Never look at the ignited arc without ANSI approved, arc shaded, eye protec-tion in a full face shield. Permanent eye damage or blindness can occur. Skin burns canoccur. Never breath arc fumes.

8. Press (and hold) the Torch Trigger Switch and stroke the area to be welded with theelectrode wire to ignite the arc.

Never tap the electrode wire into the welding surface to ignite the arc. This damagesits external coating on the electrode which prevents oxygen in the air from coming intocontact with the molten metal, causing it to oxidize.

9. Once the arc is ignited, tilt the electrode wire forward at anangle of about 35°. Refer to the illustration at right.

The wire feeds automatically at a speed dependent on theMin. or Max. current setting. The wire speed can also beadjusted using the Wire Feed Speed Control.

Note: If too much current is drawn from the MIG Welder, the Ther-mal Overload protector will activate, the red Overload indicatorwill light, and the Arc Welder will turn off until it cools down. If thishappens, turn the On/Off Switch to the OFF position and wait about 3 ~ 5 minutes.

10. When the weld is complete, lift the Welding Torch handle electrode wire clearly awayfrom any grounded object, remove your Face Shield, and turn the On/Off Switch to theOFF position.

11. Unplug the power Line Cord from the electrical outlet.

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Troubleshooting

Symptom Possible Cause Checks and Remedies

MIG Welder does notwork when turned on.

No power to MIG Welder.Check Line Cord and plug. Check facility circuitbreaker.

Overheated during use. In overload mode; Allow to cool down.

Wire does not feedproperly.

Insufficient wire feed spring tension. Tighten spring tension knob. See photo on page 6.

Wire guide sheath blocked. Clean or replace wire sheath.

Wire spool axle nut too tight. Loosen nut so reel moves freely.

Braking on wire reel excessive. Loosen brake using adjusting screw.

Wire reel has oxidized, poorly woundor quality wire.

Replace wire reel.

Reduced weldingpower.

Ground Cable not connected or poorconnection.

Check that the Ground Cable Clamp is securelyattached to the metal being welded. This area shouldbe cleaned down to the metal and free of paint, dirtand grease.

Internal connection loose on switches.A qualified technician should open the unit and checkand tighten any loose connectors.

Faulty contactor. Check the state of the contacts and the mechanicaloperation of the contactors.

One or more rectifiers failed.A qualified technician should open the unit and checkfor burnt rectifiers and replace.

Porous or spongywelds.

No gas; Little gas. Check presence of gas and supply line and pressure.

Clogged holes in Welding Torch headdiffuser.

Clear clogged holes using compressed air.

Solenoid valve blocked.A qualified technician should open the unit and checksolenoid operation and electrical connection.

Poor quality gas or wire. Gas must be very dry. Use a moisture filter. Use adifferent type of wire.

Gas supply does notswitch off.

Worn or dirty solenoid valve.A qualified technician should open the unit anddismantle valve, clean orifice and seating element.

Pressing Welding Torchtrigger produces noresult.

Faulty Welding Torch trigger;Disconnected or broken controlcables.

A qualified technician should open the unit andremove the torch connection plug and short-circuitthe poles. Check and repair control cables.

Overload controller defective.A qualified technician should open the unit andreplace the overload controller.

Maintenance

Caution: Before performing any maintenance on the MIG Welder, unplug the power LineCord from the electrical outlet.

1. Periodically using compressed air, open the top and side panels and blow out all dustfrom the interior.

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2. Store the unit in a clean and dry location.

3. Periodically clean out the Torch Head.

Replacing the Wire Reel

When the wire on the Feed Reel is used up, you will need to replace it as described onpage 6, step 5 through step 9.

NOTE: Some parts are listed and shown for illustration purposes only and are not availableindividually as replacement parts.

PLEASE READ THE FOLLOWING CAREFULLY

THE MANUFACTURER AND/OR DISTRIBUTOR HAS PROVIDED THE PARTS DIAGRAM IN THISMANUAL AS A REFERENCE TOOL ONLY. NEITHER THE MANUFACTURER NOR DISTRIBUTORMAKES ANY REPRESENTATION OR WARRANTY OF ANY KIND TO THE BUYER THAT HE OR SHE ISQUALIFIED TO MAKE ANY REPAIRS TO THE PRODUCT OR THAT HE OR SHE IS QUALIFIED TOREPLACE ANY PARTS OF THE PRODUCT. IN FACT, THE MANUFACTURER AND/OR DISTRIBUTOREXPRESSLY STATES THAT ALL REPAIRS AND PARTS REPLACEMENTS SHOULD BE UNDER-TAKEN BY CERTIFIED AND LICENSED TECHNICIANS AND NOT BY THE BUYER. THE BUYERASSUMES ALL RISK AND LIABILITY ARISING OUT OF HIS OR HER REPAIRS TO THE ORIGINALPRODUCT OR REPLACEMENT PARTS THERETO, OR ARISING OUT OF HIS OR HER INSTALLA-TION OF REPLACEMENT PARTS THERETO.

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Wire Feed Mechanism Assembly Drawing

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MIG Welder 131 Schematic Diagram

MIG Welder 131 Assembly Drawing

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Hand Held Shield Assembly Drawing